1. Related Applications
The present application is related to the following U.S. patent applications, assigned to the assignee of the present invention, Sony Corporation of America, Park Ridge, N.J.:
Ser. No. 07/741,329, filed on Aug. 7, 1991, entitled Non-Real-Time Film Scanning System;
Ser. No. 07/736,006, filed on Jul. 25, 1991, entitled Digital Video Processing System With Mixing Prefilter;
Ser. No. 07/746,928, filed on Aug. 19, 1991, entitled Method and Apparatus for Flare Correction;
Ser. No. 740,626, filed on Aug. 5, 1991, entitled Digitized Film Image Processing System With Bordered Split Screen Display;
Ser. No. 07/660,662, filed on Feb. 25, 1991, entitled Digital Signal Processing System Employing Icon Display;
Ser. No. 07/794,489, filed on Nov. 19, 1991, entitled Computerized Interactive Menu-Driven Video Signal Processing Apparatus and Method;
Ser. No. 07/710,704, filed on Jun. 5, 1991, entitled Digital Color Correction System and Method;
Ser. No. 07/740,623, filed on Aug. 5, 1991, entitled Digital Video Color Processor With Anti-Aliasing;
Ser. No. 07/687,962, filed on Apr. 19, 1991, entitled Digital Color Correction System Having Gross and Fine Adjustment Modes;
Ser. No. 07,846,675, filed on Mar. 5, 1992, entitled Correcting Digitized Signals To Achieve Specified Output Results For an Image
Ser. No. 07/846,675, filed on Mar. 5, 1992 entitled Correcting Digitized Signals to Achieve Specified Output Results for an Image;
Ser. No. 07,846,675, filed on Mar. 5, 1992, entitled Digitized Signals to Achieve Specified Output Results For An Image; and
Ser. No. 07,854,367, filed on Mar. 19, 1992, entitled Hardware Implementation of HDTV Color Corrector.
2. Field of the Invention
The present invention relates to the field of image processing systems, and more particularly, to tracking a subject image for tone scale reproduction when electrically converting a subject image from a first medium to a second medium.
3. Art Background
In image processing, image signals typically undergo various adjustments or corrections. For example, in film to video conversion for high definition television (HDTV), these adjustments and corrections include:
a) correction of colorimetric distortions due to film dye cross-talk, PA1 b) correction of the non-linear luminance transfer function of the film, PA1 c) correction for distortion due to video cross-talk, PA1 d) conversion of linear data into a SMPTE 240M representation. PA1 a) adjust the color of a film derived image to match that of a video derived image for seamless intercuts, PA1 b) removed localized noise, or PA1 c) process layered film mattes from different film types for smooth composition.
Additionally, in the exemplary film to video conversion for high definition television (HDTV) application, an operator may want to:
In film to video conversion, the film is illuminated so as to produce an optical image. The optical image is then projected onto an image sensing device to generate an HDTV video signal. The HDTV video signal generated in the scanning process is dependent upon a number of factors related to the set-up of the film scanning. These factors include: adjusting the light incident on the film to create the optical image; changing the light path filters; and setting an F-stop. As these adjustments are made, the film densities as represented in the HDTV video signal generated by the film scanning process also change. Although the HDTV video signal varies dependently with these adjustments, the image processing system must be calibrated to the film scanning process such that the film densities on the film being scanned correlate to a known signal level input in the image processing system. To account for these adjustments in the film scanning process, the image processing system may provide gain and bias controls for adjusting the HDTV video signal. However, because factors in set-up of the film scanning process may be unknown to the image processing system, absolute calibration through use Of gain and bias controls becomes difficult. Therefore, it is an objective of the present invention to provide an image processing system calibrated to the film scanning process.
In addition to the initial calibration, the image processing system needs to account for other factors relating to the original exposure of the film. For example, cinematographers, when recording the initial subject image on the film, may use the dynamic range of the film, for artistic purposes, in ways unknown to the image processing system. For example, a film may be exposed such that the shadows of the image begin at a point greater than the standard 0.1 density units above base plus fog. Therefore, it is another objective of the present invention to provide a means for an operator to specify which portion of the film dynamic range was used to record the subject image. Finally, the relationship between the original exposure of the film and the HDTV dynamic range is not fixed. Therefore, it is a third objective of the present invention to provide a means for placing a corrected HDTV video signal into the dynamic range of the HDTV video monitor.
As will be disclosed, the present invention provides for a method and apparatus for tracking a subject image range through the image processing subsystems such that the tone scale may be more accurately reproduced.